srm@pyuxnn.UUCP (12/05/83)
I've heard arguments for and against the use of those cassette deck (head, capstan, etc.) cleaners which are packaged in a cassette shell. I would appreciate some responses giving some evidence for or against these units. If anyone likes these, please add specific recommendations if possible. (Also, while we're at it, what about those demagnetizers similarly packaged?) Steve Marcovici ..pyuxnn!srm
mah@mit-eddie.UUCP (Mark Hamilton) (12/07/83)
I have used the TDK head demagnetizer packaged in a cassette-type box for several years now, with good results. Although I've never tried the wand type of demagnetizer (I use the TDK to get into my car deck) the cassette type seems to produce results equal to friend's wands, although I have to use it more often. I think the more frequent use is more than balanced by the flexibility and portability of the casette types. eddie!mah
emrath@uiuccsb.UUCP (12/11/83)
#R:pyuxnn:-18200:uiuccsb:5700017:000:977
uiuccsb!emrath Dec 10 21:45:00 1983
Please tell me what the good results of head demagnetizing are?
I have one of those TDK demagnetizers, and I could not detect any
difference in sound after using it. Furthermore, careful measurements
of noise levels before and after use showed no statistical difference
(less than 1dB unweighted). There is more variation from one tape
brand to the next. I did not measure distortion before and after
because I didn't have the equipment to do so.
The deck was a number of years old, with constant use, before
doing this experiment. It is an Aiwa 6900 and maybe it just never
needs demagnetization, though it is an older model ('78?) without
the new feature of an automatic built-in head demagnetizer.
I have had 4 deck models (Advent 201, Pioneer something or other,
Teac 450, and Awia 6900) since about 1973, and none of them showed
any signs of needing or benefitting from head demagnetization
(new heads, yes, on both the 201 and the 450).
Basically, I am a non-believer.wjm@whuxk.UUCP (12/13/83)
The purpose of cassette (or any other type of tape deck - audio or video) demagnetizing is to remove low level magnetism that builds up on playback heads during use - it is caused by the magnetic fields on the tape (which contain the information). Record and erase heads don't need to be demagnetized since the AC bias will remove this residual magnetism, but capstans and other metal parts in the tape path do need it. If you do not demagnetize, the residual field will build up and erase highs from the tape (the high frequency signals, since they take up less area on the tape and are more susceptable to erasure by low level magnetic fields). Bill Mitchell (whuxK!wjm)